The objective of the Children's Hospital National Medical Center (CHNMC) is to actively pursue investigations of the therapy, biology, and epidemiology of childhood malignancies through total participation in the Children's Cancer Study Group (CCSG). Investigators from CHNMC will continue to provide scientific and administrative leadership of these activities. CHNMC will enter all eligible patients from the institution and encourage entry of all eligible patients from its affiliate network on group wide studies of multimodality therapy of acute leukemia and pediatric solid tumors. CHNMC will continue to develop and participate in limited institution pilot (toxicity and/or feasibility) studies incorporation novel therapeutic strategies for CNS preventive therapy in childhood ALL with potential group-wide applicability. CHNMC will continue as one of the most active CCSG participants in investigational drug (Phase I and Phase II) studies, particularly those investigating plasma and/or CSF pharmacokinetics. CHNMC will exhibit compliance with protocol specified therapy as well as required evaluations and will submit complete and accurate data to the Operations Office in a timely fashion. CHNMC will expand its CCSG reference laboratory activity of immunophenotypic analysis for ALL studies and will continue to conduct independent and collaborative investigations of differences in cell biology utilizing biochemical parameters (polypeptide analysis, oncogene products, membrane ganglioside composition) and molecular genomic rearrangements which may provide insights of prognostic and therapeutic significance. CHNMC will participate in all CCSG cancer biology studies requiring submission of biologic samples to resource laboratories within the group. CHNMC will participate in case-controlled epidimiologic studies of childhood cancer to investigate the possible relationship of genetic predisposition and pre- and post-natal environmental factors oon the development of malignancy. CHNMC investigators will provide scientific leadership of such investigations within biologically-defined subgroups of patients with ALL, particularly infants less than 1 year of age. As the outcome for children with cancer has improved, CHNMC investigators will participate in the formulation of groupwide studies to examine the long-term impact of successful anti-cancer therapy on all aspects of growth and development.